The amplitudes are expressed in terms of a minimal basis of irrational functions by means of the same automated framework that we used in the 3-photon amplitude calculation [1]}.
Our framework performs finite-field sampling of the rational coefficients appearing in the amplitude by evaluating and combining the analytical IBP solutions from ref. [2]} and the master integral solutions from ref. [3]}.
The analytical results for the amplitude are obtained by interpolating the finite-field samples using the library FireFly [4]}.
We refer the reader to ref. [1]} for a detailed description of our framework.
